• International Journal of Industrial Entomology and Biomaterials
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• v.15 no.1
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• pp.75-78
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• 2007

To define the molecular mechanism of initiation and termination of diapause during the embryogenesis of silkworm, Bombyx mori, mRNA transcripts from diapausing eggs and diapause activated eggs were compared with differential expression using cDNA array. Among those clones, mRNA transcript from hsp20.8A, which was expressed at a high level in diapausing eggs that had been incubated at $25^{\circ}C$ for 30 days after oviposition, whereas, in the eggs exposed to $15^{\circ}C$ for 30 days, $5^{\circ}C$ for 60 days, the expression of mRNA decreased. On the other hand, the expression of mRNA during embryogenesis observed abundantly at 4 to 6 days after heat-HCl treatment and later at 9 to 10 days after just before hatching. This result was suggested for us that hsp20.8A was expressed in response to embryogenesis as well as physical stress.

• Korean journal of applied entomology
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• v.48 no.2
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• pp.221-227
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• 2009

Temperature effects on diapause termination of Paratlanticus ussuriensis eggs were studied by measuring embryonic development and hatching rates at various conditions of indoor chilling and overwintering temperatures. Diapausing eggs of P. ussuriensis did not hatch at continued incubation at $25^{\circ}C$ and even after chilling for once at either $5^{\circ}C$ or $10^{\circ}C$ for 30, 45 and 60 days. In addition, double chillings at $5^{\circ}C$ with a 90 days interval at $25^{\circ}C$ did not induce hatching of diapausing eggs. However, double chillings at $10^{\circ}C$ induced hatching at 3.6${\sim}$26.7%. When eggs were incubated at $25^{\circ}C$ after chilling for once at $5^{\circ}C$ for various periods, those weights were not changed but those chilled at $10^{\circ}C$ gradually increased to approximately 1.5 times. When 60-days-old eggs were artificially deposited under the soil at three different mountain sites in September 2007, the hatching rates of the first-overwintered eggs were 11.3, 3.5 and 4.1% and those of the second-overwintered eggs were 25.1, 21.6 and 0.4% at Hoepori, Bitanri and Hwasanri, respectively. Most eggs were hatched from mid-March to mid-April but little bit earlier in southern regions. During the hatching period soil temperatures in three tested locations were around 8 to $12^{\circ}C$. In overall, diapausing eggs of P. ussuriensis were greatly influenced by chilling temperature conditions and those repeated cycles, and may required overwintering for one or two times to hatch for the post-embryonic development.

• International Journal of Industrial Entomology and Biomaterials
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• v.9 no.2
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• pp.241-247
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• 2004

It was investigated whether or not flight has any effects on oviposition and colony development of the artificially hibernated Bombus terrestris queen and ,$CO_2$-treated queen. Flight periods were defined as 0 days (control), 1 day, 3 days and 6 days. The weights of queens after flight were 1.5-8.9% lower than those before flight depending on the flight periods. The oviposition and colony development of artificially hibernated and $CO_2$-treated B. terrestris queen were affected by the flight. Among flight periods tested, in particular, the queens start to flight for 3 days showed better flight effect than those other flight periods in the colony development, rate of colony foundation, rate of progeny-queen production, the number of worker and queen produced. But, the longer the flight periods is, the worse the oviposition and colony development of the queens hibernated artificially and $CO_2$-treated are (i.e., the 6 days-flight queen).